[linux-audio-user] More Mandrake 9.2 fine tuning...Dell latitude live fx box

[Chris Pickett]

rossen wrote:

> Chris Pickett wrote:
> 
>>>  I am still unable to run Jack at anything less than 1024 without having
>>> Xrun hell. I set the HD to DMA "on" I had apm as opposed to acpi
>>> running...turned it off and found no difference.
>>
>>
>>
>> Check that your CPU speed is not getting screwed up by the power 
>> management (i.e. you have the full 650 MHz).  I don't know if it's 
>> even a problem for Dell laptops, but it was/is for certain Thinkpads.
>>
> 
> How do you check the speed? Do you mean the settings in the BIOS?
> Because I also have a Thinkpad...

I actually took Linux off my laptop a couple of years ago because of 
this problem (and joined this list in preparation for putting it back on 
to do audio stuff, yada yada).

It's to do with some SpeedStep problem (google a little bit, you'll get 
lots of hits).

$ cat /proc/cpuinfo

will give you the speed detected at boot time (it should be lower if you 
booted off a battery).

whereas

$ cat /proc/cpufreq

should be current.

The problem has to do with the cpu slowing down when switching to 
battery power and not speeding back up when getting plugged back in, or 
something like that. There's some utility called cpudyn that might help 
you as well.

You can read about some guy's recent experience in detail here:

http://bellet.info/~bellet/laptop/t40.html

I remember it was reporting under 200 MHz when my laptop is meant to run 
at 750 MHz, and I couldn't seem to fix it at the time.  I think if you 
disable power management completely in the BIOS it's a usable workaround 
(if you don't want to mess around more than that).

Cheers,
Chris